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Although many fisheries stocks have declined precipitously throughout the world, fish farming--and especially shrimp and salmon farming--has boomed. The increasingly large scale of these enterprises is now having unforeseen ecological consequences on ocean resources through habitat destruction, effluent discharge, exotic species introductions, and heightened fish catch for feed use. Ending unsustainable production practices will require reorienting regulatory policies and fiscal incentives in shrimp- and salmon-producing counties, and enhancing restrictions on environmentally unsound practices.

We have investigated the impact of shrimp farming waste on benthic invertebrates in a mangrove estuary in southern Thailand. Stable carbon and nitrogen isotope analyses were used to assess the contribution of aquaculture feed as a nutrient source for benthic invertebrates (fiddler crabs Uca annulipes, U. bengali, and U. forcipata) and to compare the organic origin of sediments in tributaries with and without a shrimp farm. The isotopic contributions of shrimp feed to crabs varied between the tributaries: in the tributary with the farm, the crabs had higher contributions from shrimp feed, whereas there was only a small contribution from aquaculture feed in crabs from the reference tributary. In contrast, the contribution of shrimp feed to the sediment did not differ between the tributaries, the contributions to sediments from aquaculture feed were, in general, quite low. Based on these results, we suggest that, in mangrove estuaries, changes in the food sources of several surface feeder invertebrates would be an effective indicator of the possibility that aquaculture waste was affecting the benthic ecosystem.

:  The present study reports the annual variation in consumption of the sea urchin Strongylocentrotus intermedius by avian predators on a rocky shore where the culture of sea urchins has been conducted. Carrion crow and a few gull species were the most abundant avian predators and consumed a large number of sea urchins. Crows consumed mostly natural sea urchins, approximately 36 kg ww/ha per year on the intertidal rocky bench, but the gull species consumed mostly cultured sea urchins, approximately 100 kg ww/ha per year in the culture area. The seasonal variation in the amount of sea urchins consumed by crows was higher than that by the gull species, presumably because of the difference in foraging behavior in association with the seasonal tidal cycle. The natural sea urchins consumed are an allochthonous input from the subtidal to the intertidal habitat, and thus, crow predation may not affect the natural and the cultured populations of the sea urchin. The gull species consumed much of the cultured sea urchin, and thus, may be regarded as an effective predator causing damage to sea urchin culture. The results suggest that further studies are needed to determine why the gull species selectively feed on cultured sea urchins.

Safe Management of Shellfish and Harvest Waters is a new international text that exhaustively addresses the risks, monitoring and management of sewage contamination of bivalve shellfish harvest waters. It distills world-wide experience; identifies the challenges and opportunities that face the industry and suggests responses to those challenges.

Collection and culture of live foods to be used instudies of feeds for rearing finfish and shellfishlarvae in Taiwan began in 1982. Today, 31 species (49strains) of microalgae, three species (nine strains)of rotifers, one cladoceran and one copepod are holdas start culture. Microalgae are collected from localwaters and obtained from foreign collection centers.The most common genera are Chlorella,Nannochloropsis, Tetraselmis, Chaetoceros, Skeletonema, Isochrysis, and Pavlova. Someinteresting genera such as Ellipsoidion,Nannochloris, Synechococcus, and Alexandriumare also included. Three types of rotifers, i.e. L, S,and SS-type, which are classified as Brachionusplicatilis, B. rotundiformis, and Brachionus sp. are found in Taiwan waters. Among therotifers, six strains have been isolated and cultured.Another L-type strain and two SS-type strains wereobtained from foreign sources. The cladoceran Diaphanosoma aspinosum and copepod Apocyclopsroyi are the most common species used in aquaculture.Studies of live foods including their morphology,culture techniques, fatty acid composition andnutritional value as feeds have been undertaken.[PUBLICATION ABSTRACT]

The overall status of seedling production in Korea isdiscussed. In shellfish culture, suchas oyster and ark shell, seedlings are obtained bynatural seedling collection. Shellfish seedlingproduction has been decreasing rapidly due to coastalpollution and continuous dense culture over the years. This has lead to the development of artificialproduction of shellfish seedlings. However, the massproduction of seedlings in the hatchery is not yetfully developed in Korea. Isochrysis, Pavlova, Chaetoceros and Thalassiosiraare the main live food organisms for the artificialseedling production. Thesespecies can be cultured indoors, but the technology for theiroutdoor culture is not established.Marine fish culture production is growing fast. With regard to seedling production of marine fish,flounder and rockfish are the most importantcommercial species. For seedling production of thesespecies, rotifers and Artemia are the main livefood organisms. Marine Chlorella for rotiferculture is unstable at temperatures over 30 °C. Nannochloris oculata, which grows faster than marine Chlorella at temperatures over 30 °C iswidely used in the summer season as an alternative. A natural Artemia strain exists in smallquantities in areas of restricted salt fields. However, the mass production of Korean Artemiacyst is not economically feasible. Korean Artemia strain seems to have originated from theSandong Pennisula in China, because of similaritiessuch as the hatching ecology, chromosome number andnutrient composition. Currently, research is carried out toidentify a new live food organism that can substitute rotifersand Artemia. The cost of feedincluding live food organisms is 30-60% of the totalproduction cost for seedling production of marine fishin Korea. Therefore, new and inexpensive artificialformulated feeds should be developed.[PUBLICATION ABSTRACT]